This invention relates to an internal combustion engine in which the engine is supercharged by both a rotary blower and a turbocharger wherein the rotary blower comprises a Wankel-type compressor.
In prior art engines various combinations of precharging devices have been proposed to compress air delivered to internal combustion engines of the reciprocal piston type. The most common charging system is a turbocharger which charges the engine using a centrifugal compressor driven by a turbine that is powered by exhaust gases.
In a more complex system applicants have proposed using both a turbocharger and a positive displacement rotary expander/compressor, which like the turbocharger has one side of the unit driven by the exhaust gases and the other side operated as a compressor.
The unique combination of the turbocharger and the rotary compressor/expander was considered to comprise the best combination of the turbocharger and a Wankel-type unit. However, unexpected results were obtained when both sides of the rotary Wankel-type unit were used as a compressor and driven by power from the engine shaft.
At lower speeds of operation, the turbocharger delivers no compression and all of the compression is provided by the rotary compressor operating as a blower. At mid-range speeds both the turbocharger and the rotary compressor contribute and develope an enormous compression. At high speeds, the turbocharger develops sufficient compressed air to not only power the engine, but drive the rotary compressor which operates as an air motor.
The requirement for a "waste gate" which allows exhaust gases to bypass the turbine to prevent over-rotation of the turbocompressor unit is eliminated. The once lost power is now recaptured by driving the rotary compressor connected to the engine shaft, adding mechanical energy through the engine shaft to the engine.
In effect, the combination system proposed is its own self regulator and is a substantial improvement over existing systems such as engines, utilizing a Roots-type blower or the hyperbar engine utilizing a gas turbine engine in combination with a reciprocal engine. The invented engine responds to operating conditions with sufficient quantities of air and avoids the lag encountered with turbochargers or the air supply at high power cost encountered with most conventional blowers.